Polarized electromagnetic relay



A. H. GREBE Aug. 3, 1965 3 Sheets-Sheet 1 Filed Oct. 9. 1961 E m5 H m Mm 3 W 4y B T; W wwv MW w x I y m Aug. 3, ,1965 A. H. GREBE 3,198,995

POLARIZED ELECTROMAGNETIC RELAY Filed 001:. 9, 1961 3 Sheets-Sheet 2INVENTOR. 4/ ALF/P50 H GREBE BY J5 4 46 4439 Aug. 3, 1965 A. H. GREBEPOLARIZED ELECTROMAGNETIC RELAY 3 Sheets-Sheet 3 Filed Oct. 9. 1961INVENTOR. 41mm 6/8555 ATTOKA/EV United States Patent 3,198,995 POLARIZEDELECTROMAGNETIC RELAY Alfred H. Grebe, Cheshire, Conn., assignor toAllied Control Company, Inc, New York, N.Y., a corporation of New YorkFiled Oct. 9, 1961, Ser. No. 143,905 9 Claims. (Cl. 317-472) Thisinvention relates to the art of electromagnetic devices and, moreparticularly, to a polarized relay having improved features of designand construction.

The relay of this invention has many and varied applications. It isespecially useful in environments, such as on aircraft, which may besubjected to high inertia forces due to shock, vibrations and suddenacceleration and deceleration and in which space for operating equipmentis limited. The relay may also be advantageously employed to operatevarious items of equipment including, but not limited to, one or moresingle pole or double pole switches, valves, flag indicators and thelike. By way of example, the subject relay is illustrated and describedfurther along herein in connection with a multi-pole double throw switcharrangement.

A preferred and recommended form of relay according to this inventioncomprises an electromagnet motor assembly which includes a horizontallydisposed magnetizing coil, a core member which extends through the coil,and a pair of pole pieces which are secured to the ends of the coremember and project above and below the coil. The lower portion of eachpole piece is generally U- shaped and has a pair of spaced, laterallyprojecting end parts. A non-magnetic bridge unit is positioned under thecoil and is secured to the pole pieces and to a support which is locatedbelow and in spaced relation to the coil. The bridge unit includes a topwall or deck, which spans the space between the pole pieces, and aplurality of spaced legs, which depend from the top wall and are afiixedto the support. The support is adapted to carry a plurality of switches,each of which has a pair of spaced stationary contacts and a movablecontact arm which is adapted to engage a selected correspondingstationary contact.

A vertical shaft is secured to the top wall of the bridge unit and isdisposed in the spaced between that wall and the support. The shaft ispositioned midway between the pole pieces and carries a rotary armaturehaving a pair of balanced arms. The armature comprises a permanentmagnet, a bushing extending through the center of the permanent magnetfor receiving the shaft, and a member of good magnetic material at eachend of the permanent magnet and in intimate contact therewith. Thearmature is provided with a sheath. Each magnetic member includes endportions which project through the sheath and beyond the sides ofcorresponding and end portions of the permanent magnet. One end of eachmagnetic member faces a corresponding end part of one of the U-shapedportions of one pole piece and the other end of each magnetic memberfaces a corresponding end portion of the U-shaped portion of the otherpole iece.

p A tubular actuator, which is made of an electric insulating materialand is coaxial with the shaft, is attached to and rotatable with thearmature. The actuator is provided with a plurality of circumferentiallyspaced slots that receive corresponding movable contact arms of theswitches. Portions of the actuator which define the slots are adapted toactuate all of the movable contact arms simultaneously in response topredetermined rotary movement of the armature in either direction.

When the foregoing parts are assembled, they are placed in an upstandingtubular housing which is closed at the top and open at the bottom. Theupper ends of the pole pieces register with openings in the top of thehousing and are anchored thereto. The support is positioned in andsealed to the open bottom of the housing.

The design, relationship and characteristics of the armature and thepole pieces are such that, with the coil deenergized, the armature isheld in the extreme angular position relative to the pole pieces, towhich it had last been actuated, due to the permanent magnet flux; andthe movable contact arms are flexed by the actuator so as to engagecorresponding stationary contacts. Upon upper energization of the coil,there is created electromagnetic flux which opposes the permanent magnetflux in the closed armature gap and aids the permanent magnet flux inthe open armature gap. A condition of mechanical force and flux forceimbalance occurs which causes rotary movement of the armature to itsother extreme angular position relative to the pole pieces and flexingof the movable contact arms to effect their disengagement from theindicated stationary contacts and engagements with corresponding otherstationary contacts. The parts remain in this position until such timeas the coil is energized in a reverse direction, thereby causing reverseoperation of the armature and associated parts.

The present relay embodies a number of Worthwhile features whichfacilitates manufacture and contribute to its durability and utility.Such features include the following:

(1) The electromagnet unit of the relay includes a core bushing and acore which are so designed as to permit substantial assembly of thatunit before applying the coil.

(2) The armature is a unitary cast assembly comprising a permanentmagnet, a central bushing and a magnetic member at each end of thepermanent magnet and extending beyond its sides.

(3) The electromagnet unit is fully adjustable for electromagneticflip-flop operation prior to affixing the header assembly. This isaccomplished by charging the magnet, applying alternate polarities tothe coil and adjusting the pole face alignments until the flip voltageis of equal but opposite polarity to the flop voltage. Also, thepermanent magnet can be readily charged and discharged to facilitatecleaning out foreign particles.

(4) By constructing the armature so that the ends of the permanentmagnet are readily accessible for charging and discharging, theoperating sensitivity of the relay is easily adjusted within maximum andminimum limits, the maximum operating voltage being determined by themaximum flux of the permanent magnet and the minimum operating voltagebeing determined by the minimum holding force of the permanent magnet.

(5) By anchoring the upper ends of the pole pieces to the top of thehousing, the relay assembly is attached more firmly to the housing thanotherwise. This reduces fatigue failure due to vibrations over extendedperiods of time.

(6) The legs of the bridge units are strengthened laterally by integralstraps or arms which are secured to the pole pieces.

(7) The various switch contacts are in full view for inspection,adjustment and cleaning before the relay assembly is inserted in itshousing.

(8) The movable contact arms are captured in corresponding actuatorslots. This eliminates the need for self-biasing for normally closedcontact pressures and provides positive contact pressures forwithstanding shocks and vibrations. This also substantially reduces thepossibility of contact bounce during use.

The primary object of this invention is to provide a polarized relaythat is capable of being made in a small size and that is adapted towithstand shock forces, vibra- U tions, and sudden acceleration ordeceleration during normal use.

Another object of the invention is to provide a polarized relay ofimproved design and construction, including a rotary armature which isadapted to operate a plurality of devices, such as movable contact arms,substantially simultaneously.

A further object of the invention is to provide a relay of the typeindicated that is small and lightweight in design, that is strong anddurable in construction, that is reasonable in manufacturing cost andthat is capable of performing its intended functions in a satisfactoryand dependable manner.

The enumerated objects and additional objects, together with theadvantages of the invention, will be readily understood by personstrained in the art from the following detailed description and theaccompanying drawings which described and illustrate, by way of example,a six pole double throw relay according to the invention.

in the drawings, wherein like reference characters identify like partsin the several views:

PEG. 1 is a bottom plan View of the relay;

FIG. 2 is an elevation view of the relay shown in FIG. 1;

FIG. 3 is a view in enlargement taken along line 3-3 of Pro. 1;

FIG. 4 is a view taken along line 4-4 of FIG. 3;

FIG. 5 is a view taken along line 5-5 of FIG. 4;

FIG. 6 is a view in enlargement taken along line 66 of FIG. 3;

FIG. 7 is a fragmentary view taken along line 77 of FIG. 6;

FIG. 8 is a top plan view of the armature in enlargement partly brokenaway and partly in cross section for better illustration;

FIG. 9 is a view taken along line 9-9 of FIG. 8; and

FIG. 10 is a schematic representation of the electromagnet unit of therelay and illustrates the armature and pole pieces in a relativeposition corresponding to that shown in FIG. 5.

The complete relay, as best shown in FIGS. 1, 2 and 3, includes atubular casing or housing 10 which comprises a cylindrical side wall 11and a top wall 12 having a pair of openings 13. The housing is open atits lower end and is provided with a mounting ring 14 which is securedto side wall 11. The mounting ring has a pair of diametrically opposedopenings 15 to receive attaching screws or the like (not shown).

An electromagnet motor unit is generally denoted by numeral 16 andincludes a bobbin 17 on which there is wound a magnetizin coil C that isprovided with three insulating leads, consisting of a pair of leads 18and a third lead 19, only one of leads 1% being visible in the drawings.The coil is sheathed in a protective outer wrapper 20. A core bushing21, which is made of a good magnetic material, is positioned in and isco-extensive with the hub of the bobbin. The electromagnet unit alsoincludes a pair of parallel pole pieces P and P which are arranged atopposite ends of the bobbin and are afiixed thereto by a core member 22that extends through the pole pieces and the bushing. The core member ismade from a right circular cylindrical bar of a good magnetic materialand is provided at one end with a head 23 which bears against the outersurface of pole piece P. The other end of the core member extendsthrough pole piece P and is peened over, as indicated at 24 (FIGS. 3 and4).

Pole pieces P has an inverted, generally T-shape and is formed at itsupper end with an extension 25 which registers with an opening 13 inhousing top wall 12. The lower end portion of this pole piece isgenerally U-shaped, as illustrated in FIG. 5, and includes a pair oflateral wings or end parts 26 and 27. The pole pieces are preferablyidentical. The parts of pole piece P which are the same as those of polepiece P are identified by corresponding primed numerals in the drawings.

Secured to the pole pieces and projecting downwardly therefrom is aone-piece, non-magnetic bridge unit B. Th bridge unit comprises a topwall or deck 34), which is positioned between the pole pieces and bearsagainst the upper edges of the U-shaped portions of the pole pieces; anda plurality of, namely four, spaced depending legs 31, each having anextension 32 at its lower end. Integral with deck are upstanding tabs 33and 34 which are disposed along and afilxed to corresponding edgeportions of the pole pieces, preferably by spot welding. integral witheach leg 31 is a bent lateral tab or strap 35 which bears against anadjacent part of a corresponding pole piece and is secured thereto,preferably by spot Welding, as indicated at 36 in FIG. 4.

A shaft 37 extends through a central opening (not shown) in bridge deck34 and is eened over, as indicated at 38, to obtain a firm connectionbetween these parts. The shaft is normal to the axis of the magnetizingcoil and is located midway between the U-shaped portions of the polepieces. An annular groove 39 is provided in the lower portion of theshaft (FIG. 9).

Reference is next had to the FIGS. 8 and 9 for an understanding of thedetails of construction of an armature A which is rotatable about theaxis of shaft 37. The armature comprises a permanent magnet 49 which hasa central opening (not identified in the drawings) and which isensheathed in a casing 41 that is open at its ends. The armature alsocomprises a pair of bar members 42 and 43 which are made of a goodmagnetic material, such as soft iron. The bar members bear against andform intimate contact with corresponding ends of the permanent magnet.The end portions of the bar members extend through and beyond casing 41.A bushing 44 is disposed in a central opening through the casing and thepermanent magnet and serves as a bearing member for the armature andshaft assembly. The armature is relcasably maintained on the shaft by alow-friction split ring 45 which registers with groove 39. Casing 41 isformed with a plurality of depending, angularly spaced teats 46.

The armature carries a contact actuator which is made of a suitableelectric insulating material, such as an appropriate synthetic plasticcomposition. The actuator consists of a top wall 51 (FIG. 5) and adepending tubular side wall 52. Top wall 51 is provided with a centralopening 53 to receive bushing 44 and a plurality of spaced openings 54to receive and retain teats 46 which are peened over, as illustrated inFIG. 9. Side wall 52 is provided with six equi-spaced slots 55 whichextend upwardly from its lower edge. It will be observed that actuator59 is rotatable with armature A about the axis of shaft 37.

FIGS. 3, 6 and 7 illustrate details of construction of a header assemblyH which is secured to bridge B and is positioned below and in spacedrelation to armature A. The header assembly includes a circular supportplate 56 which is provided with a plurality of peripheral slots 57 toreceive bridge leg extensions 32 (FIG. 3). These extensions are securedto the support plate by spot welding or in any other desired mannerknown to the art. The support plate carries a number of parts comprisingelectrical connections, switch contacts, and other elements that willnow be identified and described. Such parts include six pairs of fixedterminals 60 and 61 which are spaced equidi-stantly from each other andare arranged about an outer circumference; six fixed terminals 62 whichare spaced about an inner circumference; a pair of fixed terminals 63and a central fixed terminal 64. All terminals extend through supportplate 56 and are anchored thereto by corresponding masses of a suitable,rigid, insulating material, such as glass (FIG. 7). Each terminal 63 isconnected to a corresponding coil lead 18, while terminal 64 isconnected to coil lead 19. Terminals 63 and 64 are adapted to beconnected to a suitable source of electric energy supply. Atllxed toterminals 60 and 61, preferably by welding, are corresponding L- shapedstationary contacts 60a and 61a.

An electrically conductive leaf spring contact arm 66 is provided foreach pair of contacts 69a and 61a. Each contact arm is anchoredproximate one end to a corresponding terminal 62 and is equipped at itsother end with a double button contact 67 which is positioned betweencorresponding stationary contacts 6t1a and 61a. Each contact armregisters with a corresponding slot 55 in actuator 50. The parts are soconstructed and arranged that all contact arms 66 are adapted to beflexed simultaneously relative to their terminals 62 in response topredetermined increments of rotary movement of the armature and theactuator in either direction. This eifects engagement of each buttoncontact 67 with its stationary contact 60a or 61a, depending on theposition of the armature. FIG. 6 shows the button contacts in engagementwith stationary contacts 66a as a result of previous rotary movement ofthe actuator in a clockwise direction.

In the schematic representation of the electromagnet unit shown in FIG.10, permanent magnet 40 is designated as having a north pole N and asouth pole S. Also, the armature is shown at its extremecounterclockwise pivoted position relative to the pole pieces, magneticmember 43 being in contact with part 27 of pole piece P and out ofcontact with part 27' of pole piece P and magnetic member 42 being incontact with part 26' of pole piece P and out of contact with part 26 ofpole piece P. The parts are held in this position by the permanentmagnet flux which permeates from north pole N, through the upper end ofmember 43 to part 27, through pole piece P, core 22, pole piece P, part26', member 42 and thence to south pole S of the permanent magnet.

For the purpose of outlining the operation of the above-described formof the invention, it is assumed that the relay is assembled and that theparts are in relative position shown in FIGS. 3, 5, 6 and 10. It is alsoassumed that magnetizing coil C is de-energized. The coil is nowenergized in a direction to make parts 27 and 26 electromagnetic northpoles and parts 26 and 27' electromagnetic south poles. The createdelectromagnetic flux will permeate from part 27 to member 43, to part27' and thence through pole piece P, core 22 and pole piece P to part27. At the same time electromagnetic flux permeates from part 26 tomember 42, to part 26' and thence through pole piece P, core 22 and polepiece P to part 26. This results in an imbalance of forces, namely thatdue to the permanent magnet flux and that due to the electromagneticflux, such as to cause pivotal movement of armature A in a clockwisedirection, as viewed in FIG. 10, moving member 43 out of contact withpart 27 and into contact with part 27 and simultaneously moving member42 out of contact with part 26' and into contact with part 26. Upondeenergization of the coil, the parts are retained in such position. Itwill be apparent that the indicated clockwise rotation of the armaturewill cause the actuator to also rotate in a clockwise direction, asviewed in FIG. 6, and ope-rate movable contact arms 66 so that allbutton contacts 67 are simultaneously moved from stationary contacts 60ato corresponding stationary contacts 61:: (FIG. 6).

By reversing the direction of the energizing current through the coil,the above-outlined operational procedure will be reversed and the partswill return to the relative position shown in the drawings.

A further contribution to the imbalance of forces may be introduced bythe movable contact arms being made of spring-like material whichresists motion from a neutral position between fixed terminals 60 and61.

It will be appreciated by persons trained in the art that the relay ofthis invention may be readily altered by minor modifications to obtain acenter-01f or neutral position of the armature. This may be accomplishedby (1) maintaining the permanent magnet strength but providingnon-magnetic shims on the pole pieces to facilitate unlatching in termsof voltage or (2) reducing the permanent magnet strength and providinganti-freeze shims on the armature or pole pieces so that the relay willfunction as a momentary type switch which requires voltage to hold therelay in either of the two energized positions.

From the foregoing, it is believed that the objects, advantages,construction and operation of my present invention will be readilycomprehended by persons skilled in the art without further description.Although the invention has been herein shown and described in a simpleand practicable form, it is recognized that certain parts thereof arerepresentative of other parts which may be used in substantially thesame manner to accomplish sub stantially the same results. Therefore, itis to be understood that the invention is not to be limited to the exactdetails described herein, but is to be accorded the full scope andprotection of the appended claims.

I claim:

1. A polarized relay comprising a magnetizing coil, a core memberextending through the coil, a pair of spaced pole pieces secured to thecore member, each pole piece including a generally U-shaped portionhaving a pair of spaced end parts, a non-magnetic unit secured to thepole pieces, and extending across the space between the pole pieces, anarmature carried by the non-magnetic unit and pivotal about an axiswhich is normal to and intersects the axis of the coil, said armaturebeing positioned between the U-shaped portions of the pole pieces andincluding a permanent magnet and a magnetic member at each end of thepermanent magnet and in intimate contact therewith, one end of eachmagnetic member facing a corresponding end part of the U-shaped portionof one pole piece, the other end of each magnetic member facing acorresponding end part of the U-shaped portion of the other pole piece.

2. A polarized relay comprising a horizontally disposed magnetizingcoil, a core member extending through the coil, a pair of spaced polepieces secured to the core member, a support positioned below the coil,a non-magnetic bridge unit connected to the pole pieces and to thesupport and maintaining the coil in spaced relation to the support, anarmature carried by the bridge unit in the space between the coil andthe support and pivotal about a vertical axis which intersects the axisof the coil, said armature being positioned between the pole pieces andincluding a permanent magnet having a pair of free end par-ts which aredisposed to opposite sides of said vertical axis and a magnetic memberat each free end part of the permanent magnet and in intimate contacttherewith, each magnetic member including end portions which projectbeyond the sides of corresponding free end parts of the permanentmagnet.

3. A relay according to claim 2 wherein one end of each magnetic memberfaces a corresponding pole piece.

4. A polarized relay comprising a horizontally disposed magnetizingcoil, a core member extending through the coil, a pair of spaced polepieces secured to the core member, each pole piece including a generallyU-shaped portion positioned below the coil and having a pair of spacedend parts, a support positioned below the coil, a non-magnetic bridgeunit connected to the pole pieces and to the support and maintaining thecoil in spaced relation to the support, an armature carried by thebridge unit in the space between the coil and the support and pivotalabout a vertical axis which intersects the axis of the coil, saidarmature being positioned between the U-shaped portions of the polepieces and including a permanent magnet and a magnetic member at eachend of the permanent magnet and in intimate contact therewith, one endof each magnetic member facing a corresponding end part of the U-shapedportion of one pole piece, the other end of each magnet member a s rsneasee facing a corresponding end part of the U-shaped portion of theother pole piece.

5. A polarized relay comprising a horizontally disposed magnetizingcoil, a core member extending through the coil, a pair of spaced polepieces secured to the core member, each pole piece including a generallyU-shaped portion positioned below the coil and having a pair of spacedend parts, a support positioned below the coil, a non-magnetic bridgeunit connected to the pole pieces and to the support and maintaining thecoil in spaced relation to the support, an armature carried by thebridge unit in the space between the coil and the support and pivotalabout a vertical axis which intersects the axis of the coil, saidarmature being positioned between the U-shaped portion of the polepieces and including a permanet magnet and a magnetic member at each endof the permanent magnet and in intimate contact therewith, each magneticmember including end portions which project beyond the sides ofcorresponding end portions of the permanent magnet, one end of eachmagnet member facing a corresponding end part of the U-shaped portion ofone pole piece, the other end of each magnet member facing acorresponding end part of the U-shaped portion of the other pole piece.

6. A polarized relay comprising a horizontally disposed magnetizingcoil, a core member extending through the coil, a pair of spaced polepieces secured to the core men ber, each pole piece including agenerally U-shaped portion positioned below the coil and having a pairof spaced end parts, a support positioned below the coil, a nonmagneticbridge unit connected to the pole pieces and to the support andmaintaining the coil in spaced relation to the support, said bridge unitcomprising a top member beneath the coil and spaced from the support anda plurality of spaced legs extending from the top member to the support,a vertical shaft connected to the top member projecting into the spacebetween the top member and the support, an armature carried by androtatable about the shaft, said armature being positioned between the U-shaped portions of the pole pieces and including a permanent magnet anda magnetic member at each end of the permanent magnet and in intimatecontact therewith, one end of each magnetic member facing acorresponding end part of the U-shaped portion of one pole piece, theother end of each magnetic member facing a correspond ing end part ofthe U-shaped portion of the other pole piece.

7. A polarized relay comprising a horizontally disposed magnetizingcoil, a core member extending through the coil, a pair of spaced polepieces secured to the core member, each pole piece including a generallyU-shaped portion positioned below the coil and having a pair of spacedend parts, a support positioned below the coil, a nonmagnetic bridgeunit connected to the pole pieces and to the support and maintaining thecoil in spaced relation to the support, said bridge unit comprising atop member beneath the coil and spaced from the support and a pluralityof spaced legs extending from the top member to the support, a verticalshaft connected to the top member and projecting into the space betweenthe top member and the support, an armature carried by and rotatableabout the shaft, said armature being positioned between the U- shapedportions of the pole pieces and including a perma nent magnet and amagnetic member at each end of the permanent magnet and in intimatecontact therewith, each magnetic member including end portions whichproject beyond the sides of corresponding end portions of the permanentmagnet, one end of each magnetic member facing a corresponding end partof the U-shaped portion of one pole piece, the other end of eachmagnetic member facing a corresponding end part of the U-shaped portionof the other pole piece.

3. A relay according to claim 7 wherein the shaft is midway between thepole pieces and the armature is so formed as to obtain a pair ofbalanced arms which extend to opposite sides of the axis of the shaft.

9. A relay according to claim 7 including an actuator affixed to androtatable with the armature, said actuator being adapted to operate ameans, which is adapted to be mounted on the support, in response topredetermined rotary movement of the armature in at least one direction.

References Cited by the Examiner UNTTED STATES PATENTS 2,941,130 6/60Fischer et al 31717l 3,017,474 1/62 Huetten 3l717l 3,041,422 6/62Greshel 200-93 3,097,328 7/63 Sauer 317-199 LARAMIE E. ASKIN, PrimaryExaminer.

JOHN F. BURNS. Examiner.

1. A POLARIZED RELAY COMPRISING A MAGNETIZING COIL, A CORE MEMBEREXTENDING THROUGH THE COIL, A PAIR OF SPACED POLE PIECES SECURED TO THECORE NUMBER, EACH POLE PIECE INCLUDING A GENERALLY U-SHAPED PORTIONHAVING A PAIR OF SPACED END PARTS, A NON-MAGNETIC UNIT SECURED TO THEPOLE PIECES, AND EXTENDING ACROSS THE SPACE BETWEEN THE POLE PIECES, ANARMATURE CARRIED BY THE NON-MAGNETIC UNIT AND PIVOTAL ABOUT AN AXISWHICH IS NORMAL TO AND INTERSECTS THE AXIS OF THE COIL, SAID ARMATUREBEING POSITIONED BETWEEN THE U-SHAPED PORTIONS OF THE POLE PIECES ANDINCLUDING A PERMANENT MAGNET AND A MAGNETIC MEM-